Sullinger suffered a bone bruise taking a charge from the Orlando Magic's Moe Harkless on Monday. He underwent an MRI on Tuesday after sitting out practice, and lingering soreness prevented him from getting on the floor Wednesday.
He returned to practice Thursday and had said he planned to play against the Blazers.
What did the Celtics miss without Sullinger?
"We're not as good on the block, obviously, and throwing it into the post [Monday] night against Orlando, we went on a 4-0 run when we were down 19-15 by just throwing him the ball," Celtics coach Brad Stevens said. "So it gives us a little bit more flexibility playing inside out. That's been when we've been at our best. Nonetheless, we still have guys that can play down there, but he probably is our best low-post player."
The 6-foot-9 Sullinger is averaging 11.3 points and 5.1 rebounds in 19.7 minutes per game (seven appearances). He is a team-best plus-38 this season.